A standard lighter with delayed gas release such as described in U.S. Pat. No. 4,773,849 of F. Schachter and French patent 2,273,992 has a body forming a reservoir filled with a supply of a normally gaseous combustible stored as a liquid, a pressure-reducer/evaporator on an outlet of the reservoir, and a burner/valve that closes the gas outlet. This valve is operated by a lever pivoted about an axis orthogonal to that of the burner/valve and has a front end normally applied against a shoulder of the burner/valve and constantly maintaining the valve closed against a force exerted on it by the gas. The lever also has a rear operating end that is constantly acted on by a spring urging it pivotally in a direction corresponding to closing of the valve, that is pressing the valve shoulder axially downward. Such a lighter is lit by pressing down the rear end of the lever against the above-mentioned spring to free the valve so that it opens under the action of the pressurized gas and so as to operate slightly afterward a mechanism for producing a lighting spark.
It is easy to see that it is preferable that opening of the valve only take place at the end of actuation of the lever, not only in order that gas is only released at the instant of production of the spark in the case that this is after the starting of movement of the lever so as to favor lighting but also in order that the time the valve is opened is reduced as much as possible. Since in addition it is common that such a lighter is squeezed in the pocket of a garment or a bag it is possible that one of the conditions it is subject to tends to tip the lever somewhat in a direction opening the valve and, unless there is a neutral stroke, such tipping inherently leads to a useless loss of gas.
It is also particularly important that the valve only be opened at the end of the travel of its control lever when the lighter is a childproof lighter. Such a device, as described in copending patent application 651,332 filed Feb. 9, 1991, has a mechanism for blocking the control lever in the closed position of the valve that is capable of being maneuvered into an out-of-the-way position in order to permit lighting of the flame but that is automatically returned to the active blocking position after each actuation of the control lever.
This childproofing mechanism comprises movable abutments normally situated in the path of a part of the rear end of the control lever. In order that this mechanism perfectly performs its function it is necessary that it be opposed to any pivoting of the lever, even through a very short stroke, because as soon as it is released by the control lever the valve is pushed into the open position by the pressurized gas freed by the pressure- reducer/evaporator. However, manufacturing tolerances do not allow one to eliminate all play between the control lever and the movable abutments of the blocking mechanism and in addition the progressive deformation of the lever, in particular caused by heat of the lighter flame, tends to increase this play to the detriment of safety.
In French patent 2,280,029 of M. E. Coggiola a lighter of the above-described type is known in which opening of the valve by the control lever is delayed by the use of a second biasing means interposed between the first spring and the valve and set to act on the valve in series and in the same direction as the first spring, that is in the direction of closing of the valve but with a force less than that of the first spring but more than that caused by the pressure of gas and tending to open the valve. Thus when the lighter is in the rest position, that is when the valve is closed, the first spring maintains the second biasing means in maximum activated position, that is compressed, and the sum of the two forces is opposed to opening of the valve. It is only during actuation of the control lever in the direction of opening the valve that the second biasing means continues all alone, to start with, to oppose opening of the valve and it is only on further actuation of the control lever that there is a sufficient deactivation of the second biasing means to allow opening of the valve. Thus the presence of this second biasing means delays opening of the valve by a time corresponding to a predetermined fraction of the angular travel or free path in the closing direction of the valve of the control lever for opening and closing.
In the lighter of the above-cited French patent the second biasing means if formed by the control lever which to this end is shaped to have an elastically deformable section between its front end bearing on the burner/valve and its rear end. The front end of the control lever which completely or partially surrounds the upper end of the burner/valve is divided by a V-section notch into upper and lower sections connected to each other by a web of elastic material forming an elastic hinge. The lower section is normally inclined downward but can be pushed elastically toward the upper section with a force smaller than that caused by the first spring but greater than that caused by the pressure of the gas under the valve. While giving complete satisfaction as far as function is concerned, this lighter has the disadvantage of being expensive because of the price of its control lever.